I met my best friend in school when I was 7 years old, w. We took classes together until the end of primary education, then, we didn't tookake classes together anymore because we moved to different schools, b. But we've still talkinged to each other over thise years.

I met my best friend in school when I was 7seven years old, w. We took classes together until the end of primary school/education, then. Then/Unfortunately, we didn't tookake classes together anymore because we moved to different schools, but w. Nevertheless, /Despite that, we're still talking over thisese years.

Usually, you would spell out numbers 1 to 9. Also, I made suggestions based on how you want to structure your piece. If you want to write your entry in a neutral, chronological order, you can use sequential terms like first, then, etc. If you want to make it more emotional, then you can use words like unfortunately to emphasize how upset you felt not taking classes with your best friend from school.

I met my best friend in school when I was 7 years old, w. We took classes together until the end of primary education,school. But then, we didn't tookake classes together anymore becauseafter we moved to different schools, but we still talking over this. However we are still talking after all these years.

Careful about constructing run-on sentences! I chose "however" to start the last sentence to contrast with the previous sentence that said you sadly were no longer classmates after shifting to different schools.